Hydraulic machines



R. B. WILL! Nov. 1, 1966 HYDRAULIC MACHINES Filed Jan. 17, 1966 INVENTOR.

R/CHA/FD 8. W/LL/ ATTORNEYS.

United States Patent Ofiice 3,2825% Patented Nov. 1, 1966 3,282,563 HYDRAULIC MACHINES Richard B. Willi, Norristown, Pa., assignor to Baldwin- Lima-Hamilton Corporation, Philadelphia, Pa., a corporation of Delaware Filed Jan. 17, 1966, Ser. No. 521,075 5 (Ilaims. (Cl. 253-117) This invention relates to hydraulic machines and more particularly to hydraulic machines having a means for admitting or withdrawing air below a runner thereof to improve the operation thereof. The hydraulic machine may be operated as a pump, a turbine, or pump-turbine.

A hydraulic machine which can pump water or generate power is known as a pump-turbine. Such a hydraulic machine has a casing, draft tube, riunner, stay ring, head cover, discharge ring, and wicket gates which are made movable in order to control the rate of water flow through the machine. The hydraulic machine is either driven by or drives an electrical unit which can operate as a synchronous motor or generator. Direction of rotation can be reversed from the pumping to the generating mode. When the direction of rotation is to be reversed from pumping to generating mode, special electrical equipment and switch gear are necessary to adapt the motor-generator to the mode of operation desired, namely pumping with direction of rotation appropriately selected or generating with a reversed direction of rotation. It is also possible to provide a pump-turbine which has a uni-directional rotation.

This invention may be used to improve the operation of a hydraulic machine such as a turbine, pump, or pumpturbine. These hydraulic machines are designed so their efliciency is best at full load. In the operation of such machines with part-load or overload or at over speed, pressures below atmospheric pressure may be set up in the region of the runner, which may lead to cavitation phenomena and unstable flow condition, which may cause noises, roughness of operation, and vibration. Such phenomena may be reduced or entirely avoided by the supply of air to points at which the said negative pressures occur. When pressure within the tube remains above atmospheric pressure, compressed air may be substituted in lieu of atmospheric air to accomplish the same purpose. Depending upon the particular state of operation or transient condition existing, the admission of air may be more effective at a particular location extending from the inner periphery of the tube to the longitudinal axis of the tube. When the machine is operated as a turbine the tube is a draft tube and when the hydraulic machine is operated as a pump the tube is a suction tube.

At other times, no air will be required. When no air is required, it is desirable to remove any obstructions from within the draft or suction tube. Furthermore, when the hydraulic machine utilized is a pump-turbine, it is also desirable to provide a means for quickly removing compressed air from the draft tube after the water level has been depressed by such compressed air, and the electrical unit is functioning as a motor with the desired operating speed. During the period when the hydraulic machine is being brought up to operating speed, the drag on the motor is greatly reduced by allowing the runner to spin in air rather than in water. After the pump-turbine has attained the desired speed and the motor has been synchronized with the electrical line frequency, the compressed air must be with-drawn before the wicket gates are opened for the purpose of pumping water. If the compressed air is not withdrawn, a large mass of air will be pushed into the discharge pipe and may create pressure surges. Also, it is necessary for priming purposes as a pump to set the pump-turbine below the level of the suction water. The submerged position of the pump-turbine below the level of the suction water necessitates the use of compressed air to depress the water below the level of the runner.

The object of this invention is to supply or withdraw air from beneath the runner of a hydraulic machine in a simple manner adapted to the particular operating conditions of the hydraulic machine. In accordance with the invention, for this purpose, a double acting cylinder having a retractable air injector or withdrawer is provided. The air injector or withdrawer is adapted to be selectively moved so that air may be injected or withdrawn from any desired radial position within the draft or suction tube. When no air is required, the air injector may be completely retracted so that no obstruction exists within the draft or suction tube.

It is an object of my invention to provide an improved arrangement for introducing air into a water stream of a hydraulic machine at various selective positions.

It is another object of my invention to provide a double acting cylinder which has an air injector integral therewith.

It is another object of my invention to provide an air injector or withdrawer for a hydraulic machine which can be completely removed from within a draft or suction tube of a hydraulic machine so that no obstructions are provided within the draft or suction tube when no air is required therein.

It is another object of my invention to provide a movable air injector capable of injecting or withdrawing air at desired positions within a draft or suction tube.

It is another object of my invention to improve the smoothness of operation of hydraulic machines by introducing or withdrawing air below the runner or impeller thereof to reduce roughness of operation, cavitation, and vibration of the hydraulic machine.

It is another object of my invention to provide means to quickly remove compressed air from within a draft or suction tube of a pump turbine.

It is another object of my invention to provide for the admission of compressed air into the draft or suction tube of a pump-turbine at any desired radial position near the vertical axis of the tube when changing the mode of operation from generating or pumping to the synchronous condenser mode where the motor is made to spin in air with the electrical unit driving it as a motor.

Other objects will appear hereinafter.

For the purpose of illustrating this invention, there is shown in the drawings a form which is presently preferred; it being understood, however, that this invention is not limited to the precise arrangements and instrumentalities shown.

FIGURE 1 is a partial section view of a hydraulic machine having the air injector of this invention attached thereto.

3 FIGURE 2 is an enlarged section view of the double acting cylinder of this invention cooperating with a draft or suction tube of a hydraulic machine.

In FIGURE 1 there is illustrated a hydraulic pumpturbine machine generally designated as it While a propeller turbine is illustrated in the drawings, it is to be expressly understood that the propeller turbine is shown for purposes of illustration only. The air injector and withdrawer of this invention can be used in various other types of hydraulic machines such as Francis turbines or the like.

The pump-turbine has a runner 12 having blades 14 connected thereto. A spiral casing 18 is provided through which water is admitted when the machine is operating as the turbine. The water passes wicket gates 16 into the runner intake 17 Where it strikes the blades 14 and causes rotation of the turbine in a manner well understood. Thereafter the water flows through a draft tube 20, which is a suction tube when the hydraulic unit operates as a pump. The blades 14 and the runner 12 are mounted on a shaft 22.

The Wicket gates 16 are of the usual type wherein each gate is rotatable about its own axis and is actuated by a shifting ring 26. The shifting ring 26 is connected to the wicket gates by connecting links 28 and gate arms 30. The shifting ring 26 is operated preferably by the usual type of fluid actuated piston and cylinder type of servo-motor 32, the piston rod 34 of which is connected to the shifting ring. Any usual type of speed governor (not shown) may be employed so as to control the supply and discharge of actuating fluid to the motor 12 automatically in accordance with speed variations of the unit from normal.

When the pump-turbine 10 operation is reversed to operate as a pump, fluid is drawn through the suction tube 20 and pumped into the spiral casing 18. The unit thereafter operates as a pump in the conventional manner.

A double acting cylinder 36 is adapted to be attached to the casing 18. FIGURE 2 shows a. piston 38 housed within the cylinder 36. An air injector or withdrawer 40 extends through the cylinder 36 and is integrally attached to the piston 38. The air injector or withdrawer 40 has a passage 41 therein and an opening 43 to its end for allowing air to be passed therethrough. A coupler valve 42 having a bleed port to atmosphere (not shown) may be provided on one end of the air injector or with-drawer 40 which may have an air supply conduit 44 connected thereto. A conduit 46 and a conduit 48 are provided at opposite ends of the double acting cylinder 36. Conduits 46 and 48 terminate at a supply and exhaust-valve 54. The valve 54 is adapted to admit air into either conduit 46 or 48 alternatively. When the supply and exhaust 54 is in communication with conduit 46, the conduit 48 is connected to atmosphere through the valve 54. Conversely, when the valve 54 is in communication with the conduit 48, the conduit 46 is connected to atmosphere through the valve 54. Connected to the valve 54 is a conduit 56 which is adapted to be supplied from a source of air for use in the cylinder 36.

The conduit 44 is adapted to supply air to the injector or withdrawer 40. The air which is supplied may be either under pressure or at atmospheric pressure. The same source may be used to supply the conduit 56 and the conduit 44.

When air is supplied through the conduit 46 the piston 38 is move-d towards the draft or suction tube 20 thus causing the injector or withdrawer 40 to move radially inwardly with respect to the draft or suction tube. A bleeder 52 is provided to control the rate of flow of air into the conduit 46. Thus, incremental displacement of the piston 38 can be accurately controlled. The piston 38 may be moved to any desired position so that air may be injected into the draft of suction tube in a variety of positions.

The piston 38 is provided with bosses 39 integral therewith. The bosses 39 provide limit stops for the piston 38 so that the piston 38 will not be allowed to move into flush engagement with the opening of either of conduits 46 and 48. Thus, piston 38 cannot block on air which is directed through the conduits 46 and 48.

When it is desired to withdraw compressed air from within the draft or suction tube 20, such air may be withdrawn through the passage 41 in the air injector or withdrawer 49. The compressed air may be vented to atmosphere through a bleed port on the coupler valve 42.

Thereafter, if it is desired to remove the air injector or withdrawer 40 from the draft or suction tube or to' retract the injector or withdrawer to any desired position, air may be supplied through conduit 56 and directed by valve 54 into the conduit 48. This causes the piston 38 to be moved in a direction away from the draft or suction tube and the injector or withdrawer 40 moves therewith. A bleeder 50 is provided to control the rate of flow of air into the conduit 48. Thus, incremental displacement of the piston 38 may be accurately controlled.

It is readily seen that the double acting piston 36 of this invention can be utilized in either a pump, a turbine, or a pump-turbine. It is further apparent that the air injector or Withdrawer may be used on a propeller turbine as shown or on other types of hydraulic machines such as a Francis turbine or the like. Under conditions where air is needed to improve the operation of a hydraulic machine a double acting cylinder can be utilized to provide air to thereby improve the operation of such hydraulic machine. It is further readily seen that depending upon the particular state of operation of transient condition existing, the admission of air may be more desirable towards the center of the draft or suction tube or at the side wall of the draft or suction tube. The injector or withdrawer of this invention permits either condition to be met and also permits all obstructions to be removed from the draft or suction tube when no air is required in the draft or suction tube. It further permits compressed air to be withdrawn from any desired position within the draft or suction tube.

The present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof and, accordingly, references should be made to the appended claims, rather than to the foregoing specification as indicating the scope of the invention.

I claim:

1. A hydraulic machine comprising a rotating element, said rotating element including a shaft and a runner connected to said shaft, a plurality of blades connected to said runner, and selectively positionable means for injecting or withdrawing air beneath said blades at various positions with respect to said blades.

2. A hydraulic pump-turbine machine of the type embodying a housing with a fluid passage therethrough, a runner in said passage, wicket gates mounted ahead of said runner, a tube, said tube being a draft tube when said machine is operated as a turbine, said tube being a suction tube when said machine is operated as a pump, and means to supply air to the tube beneath the blades, said means being selectively positionable for introducing air at different locations within said tube.

3. A hydraulic pump-turbine as set forth in claim 2 wherein said selectively positionable means may be entirely retracted from said draft or suction tube when no air is required in said tube and wherein said means to supply air can be selectively operated to withdraw air from said tube.

4. A hydraulic pump-turbine as set forth in claim 3 wherein said means includes a cylinder having a piston therein, said piston having an air injector integral therewith, and said piston being selectively movable to any desired position within said cylinder so that the air injector may introduce air into said tube at locations extending from the inner periphery of said tube to the longitudinal axis of said tube.

5. A hydraulic turbine comprising a housing having a fluid passage therethrough, a runner in said passage, wicket gates mounted ahead of said runner, blades mounted on said runner, a draft tube positioned beneath said blades, a selectively positionable air injector for injecting air into said draft tube beneath said blades for improving the smoothness and operation of said hydraulic turbine, said selectively positionable air injector comprising a cylinder having a piston therein, said piston No references cited.

MARTIN P. SCHWADRON, Primary Examiner.

E. A. POWELL, IR., Assistant Examiner. 

1. A HYDRAULIC MACHINE COMPRISING A ROTATING ELEMENT, SAID ROTATING ELEMENT INCLUDING A SHAFT AND A RUNNER CONNECTED TO SAID SHAFT, A PLURALITY OF BLADES CONNECTED TO SAID RUNNER, AND SELECTIVELY POSITIONABLE MEANS FOR INJECTING OR WITHDRAWING AIR BENEATH SAID BLADES AT VARIOUS POSITIONS WITH RESPECT TO SAID BLADES. 